The present invention relates to an image forming apparatus, and particularly relates to a medium feeding cassette for storing a medium (for example, a recording sheet) to be fed to a main body of the image forming apparatus.
In a conventional sheet feeding cassette, a cassette extension member (i.e., a slide member) is mounted to a cassette main body so as to be movable with respect to the cassette main body. The cassette extension member is locked by a locking mechanism in a predetermined position with respect to the cassette main body. To be more specific, in order to enlarge a space for storing recording sheets, the cassette extension member is slid to a protruding position from the cassette main body and is locked therein. Such a sheet feeding cassette is disclosed in, for example, Japanese Laid-open Patent Publication No. H6-48590 (Page 3, FIG. 1).